Physical Stability for Preventing Damage in Exhibits

General Guidelines

• Conduct a stability risk assessment. Consider mounting requirements for object stability and safety. Particular concerns include large and/or heavy objects or those not enclosed in a display case. Consider potential visitor interaction with objects and exhibit materials. Identify the likelihood of seismic activity and building vibrations.
• For information on seismic activity and building vibrations:  http://news.getty.edu/getty-museum-collaborates-on-seismic-mitigation-research-project-with-hellenic-ministry-culture-and-sports-and-national-technical-university-athens.htm, https://www.preventionweb.net
• Evaluate transit, mounting, and installation requirements. This is of specific concern for oversized and heavy objects. Riggers and/or structural engineers may be needed to provide expertise.
• Design secure object attachments, mounts, and display components to provide long-term support. Securely mount objects to case surfaces, on platforms, to walls, or floors. Make sure case decks, risers, and any other display components are secured together. Secure freestanding cases to the floor or ceiling; temporary walls must be well secured.
• Facilitate authorized access to the objects. Each object in an exhibit should be readily removable without having to remove or disturb adjacent objects. Mounts and attachments should facilitate maintenance and de-installation.

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Guideline: Exhibit mounts and supports must be carefully designed to promote object safety and fulfill the Conservation Requirements

An object mount can play an active role in conservation by protecting an object from such risks as theft or physical damage. A well-designed mount will provide support to weak areas, distribute weight safely across a brittle or fragile object, and secure loose parts from moving unintentionally. Mounts can also provide cushioning, which will protect the object from shocks and vibration. Conversely, and as important, a poorly designed mount can create damage by physically stressing an object or exposing it to contact with harmful materials. Because proper mount design is critical to object preservation, it should begin early in the design stage and should involve conservator input as necessary.

Best Practice: The mounting requirements of exhibit objects are planned early in the design phase.

Why is it important to plan mounts early in the design phase?

Many exhibit design decisions will have an impact upon the style, requirements and cost of the exhibit mounts, the most critical being whether to display objects in an open format or within exhibit cases. The exhibit team must therefore make the initial decisions about object presentation early in the design phase. Furthermore, there are many different preservation-responsible methods to support and mount any object, and discussing options with a conservator early will help with making a selection.

The curator, conservator, and other relevant team members should discuss mounting options with the designer, preparator, and installer. Broad decisions to be made include:

• To mount or not to mount
• If mounting, whether to use generic or custom mounts
• The particular design and style to be used, especially for custom mounts
• Methods of attaching object to mount and mount to exhibit structure

Several issues common to custom mounts can have an impact on conservation and must be addressed. Discussions should resolve the following questions:

• The acceptable viewing angle, appearance and the geometry of the object on display
• Whether the objects should be displayed in a vertical or a shelf-supported position
• How highly-vulnerable objects such as textiles and documents will be mounted
• Size of the mount
• Materials used to construct the mount
• Finishing of the mount
• Method of holding the object
• Method of attachment to the structure or exhibit furniture
• Whether a mounting system will be used—such as support wires suspended from the ceiling or an attachment system for the walls or floor

Proper mounting can take considerable time and resources to produce. There may not be enough time to mount all objects safely. In which case alternative objects could be selected or generic rather than custom mounting could be used.

Best Practice: Design of mounts promotes object-safety and always provides appropriate support

Why is appropriate mount design essential to the conservation of exhibit objects?

An exhibit’s design interfaces with the museum collection at the exhibit object mount. It is here that actual contact is made with the object. Therefore, the quality of this exhibit base is paramount. And while a mount can promote object safety, a badly designed mount can serve as an agent of deterioration.

A properly mounted object is well-supported and protected from slippage, jarring, and movement from air currents, vibration, and visitor activity. However, improperly designed or constructed mounts can scratch, bend, discolor, corrode, or otherwise damage an object. Support over the entire length, width, or diameter of an object often requires that the mount be padded to the object’s contour. Support is especially crucial for objects that are pliable or flexible by nature or due to advanced deterioration. Mount design must anticipate the tendency for organic materials to droop, sag, or experience dimensional changes. Textiles and other fiber-based materials are susceptible to creasing, tearing, and deformation.

Mountmaking is a specialized field and is often done by metal-workers or other specialists in collaboration with conservators.

What are the main recommendations to ensure object-safe mount design?

An appropriately designed mount will strive to protect the integrity of the object. It is never acceptable to alter, dismantle, or reconfigure an object to fit a mount. To protect objects adhere to the following recommendations:

• Present the object in the desired orientation with the least stress on materials. Vulnerable items, such as fragile textiles and paper, should be displayed at angles less than 45 degrees.

• Support the entire object. The object's center of gravity or originally intended attitude should be considered when designing a mount. The mount must prevent physical stress or unbalanced weight distribution and should support the object over its entire length, with separate support for any attachments.

• It is imperative that mannequins and support forms are sized appropriately to fit textiles. In older or degraded pieces, the actual woven fabric as well as the seams may split under pressure. Muslin linings and backing are often needed to reinforce and protect garments and hanging textiles. These materials should be applied by a qualified conservator.

• Provide adequate support for flexible objects. Create custom-padded mounts for fragile organic materials, such as textiles that support the structure over its entire contour. Textiles, papers, organic materials, and other susceptible objects should not be creased or folded, nor should heavy objects be placed directly on top of them.

• Support all parts independently. Fragile objects, including textiles, should be supported over as large an area as practical. Attached parts, such as straps, may require independent support.

• Stabilize the position of an object, especially if its shape is irregular.

• Stabilize objects from vibration. The mount design should reduce vibration when a case is opened or bumped. A mount should fit its object with precision to prevent vibration and abrasion. An object-safe cushioning material is often required to buffer the adverse effects of vibration.

• Ensure adequate security for mounted objects. Attach mounts and supports to the wall with appropriate hardware such as bolts and metal wire. Anchor the wall fastener firmly to the wall and be sure that it can support the weight of the supported object. Use mechanical designs to lock mounts in place.

• Ensure that the object will be attached safely to its mount. Never glue an object to a mount. Do not fasten a mount around an object so that removing it is difficult.

What are the main options when selecting exhibit mounts?

Generic and custom mounts: Need to include broad discussion of situations in which it’s okay to choose generic mounts to display an object, and situations in which custom-made must be used.

Exhibit mounting design generally falls into two categories—generic and custom mounts:

Generic mounts

Examples of generic mounts include:

• Book cradles
• Stands for paper objects
• Boxes or pedestals for three-dimensional objects
• Ring stands for pottery
• Pressure mounts for textiles and papers

Generic mounts may require some adjustment or additional cushioning material and fastening of the item to provide even support for the object. Book cradles, for example, must be sized for the volume; padding can be contoured to the spine and covers. Generic mounts can be purchased, or they can be made or adapted by staff members who have good manual skills and a basic knowledge of object handling. Because a generic mount does not suspend an object, it can be installed using common sense. A conservator rarely needs to be consulted.

Usually, generic mounts have the following characteristics:

• They require no consultation with a conservator.
• They require little object handling and fitting.
• They require only rough measurements.
• If produced in-house, they require some skills of a mount fabricator.
• They usually present the object in a simple, planar orientation.
• They can be purchased as stock items

Custom mounts

These are made to the specifications of a particular object and therefore always require technical skill and a knowledge of objects. These mounts are often constructed by a qualified mount maker or exhibit preparator in consultation with a conservator. Constructing a custom mount may be part of the conservation treatment for a particularly fragile object.
Custom mounts have these characteristics:

• They usually require consultation with a conservator.
• They require object handling, individual measurement, and fitting.
• They can be designed and fabricated by a highly skilled mounting specialist.
• They present the object in a well-supported, suspended, or otherwise complex orientation.

Custom mount types include:

• Metal rod "T" mounts
• Metal rod “spider” mounts
• Drop mounts or rod and sleeves
• Pin mounts
• Straps or clips
• Mannequins or partial three-dimensional forms

When should a conservator be involved in mount design?

The conservator should be involved in decisions about the mounting of all vulnerable and problematic objects. If a great deal of intervention with the object is needed, conservators may fabricate part or all of the mount themselves. [Need Links to mount design documents]

Best Practice: Object-safe materials are used to construct mounts

Why is it essential to use object-safe materials to construct mounts?

Object mounts come into direct contact with an object and therefore should be made from chemically-stable and non-abrasive materials. Even when an object is only on short-term exhibit, its mount is commonly retained for the object’s long-term storage. Therefore even for short-term exhibits, a mount should be constructed from tested and stable materials that will not deteriorate over time or expose the object to off-gassing.

What materials can be used to construct object-safe mounts?

Rigid acrylic or polycarbonate, brass rod and straps, high-density polyethylene foam, conservation-grade paper products or textiles are appropriate for conservation use.

• Metal mounts (and other reactive materials) must always be covered with an inert fabric or foam or coated with a barrier such as an acrylic resin or silicon rubber to prevent reactions between an object and the metal. Cushioning material may also be used to provide a smooth contact surface, and it may be required to pad the object.

• Padding and cushioning materials: Only use high-quality padding and cushioning materials, such as polyethylene foam, polyester batting and felted material, 100% cotton fabrics, and acid-free buffered tissue paper.

• Mannequins and forms that support garments must be made from inert materials, such as polyester batting or polyethylene foam. As an alternative, use cotton fabric to buffer the textile from direct contact with material of unidentified composition, such as sealed wood and certain foams.

[For more information on object-safe materials see Materials Standard*.]